Switch Mode Power Suppliers (SMPS)
Posted: Sun Oct 25, 2009 11:19 pm
The electric power is not normally used in the form in which it was produced or distributed. Practically all electronic systems require some form of power conversion. A device that transfers electric energy from a given source to a given load using electronic circuits is referred to as Power Supply (although "power converter" is a more accurate term for such a device).
A typical application of a power supply is to convert utility AC voltage into regulated DC voltages required for electronic equipment. Nowadays in most power sources the energy flow is controlled with power semiconductors that are continuously switching on and off with high frequency. Such devices are referred to as switch mode power supplies or SMPS. They offer greater efficiency compared with linear supplies because a switch can control energy flow with low losses: when a switch is on, it has low voltage drop and will pass any current imposed on it; when a switch is off, it blocks the flow of current. As the result, in such a switch the power dissipation which is the product of voltage and current, can be relatively low in both states. SMPS are also smaller in size and lighter in weight due to the reduced size of passive components and lower heat generation. The industry trend toward miniaturization, advancements in power electronics technology, as well as various energy efficiency regulations have made "switcher" the dominant type of power supply across practically the full spectrum of applications. Most of the switchers manufactured today for AC input applications include a PFC front end.
In general, SMPS can be classified into four types according to the form of input and output voltages: AC to DC (also called off-line DC power supply), DC to DC (voltage or current converter), AC to AC (frequency changer or cycloconverter), and DC to AC (inverter).
The field of engineering that deals with the design and analysis of power conversion circuits and devices is called power electronics. This site is an information guide to power electronics and SMPS. Here you will find tutorials, tools, reviews, schematics, and other free online resources on all aspects of switching power supply design and selection, information on other energy conversion sources, as well as basic electrical engineering and electronics reference.
A typical application of a power supply is to convert utility AC voltage into regulated DC voltages required for electronic equipment. Nowadays in most power sources the energy flow is controlled with power semiconductors that are continuously switching on and off with high frequency. Such devices are referred to as switch mode power supplies or SMPS. They offer greater efficiency compared with linear supplies because a switch can control energy flow with low losses: when a switch is on, it has low voltage drop and will pass any current imposed on it; when a switch is off, it blocks the flow of current. As the result, in such a switch the power dissipation which is the product of voltage and current, can be relatively low in both states. SMPS are also smaller in size and lighter in weight due to the reduced size of passive components and lower heat generation. The industry trend toward miniaturization, advancements in power electronics technology, as well as various energy efficiency regulations have made "switcher" the dominant type of power supply across practically the full spectrum of applications. Most of the switchers manufactured today for AC input applications include a PFC front end.
In general, SMPS can be classified into four types according to the form of input and output voltages: AC to DC (also called off-line DC power supply), DC to DC (voltage or current converter), AC to AC (frequency changer or cycloconverter), and DC to AC (inverter).
The field of engineering that deals with the design and analysis of power conversion circuits and devices is called power electronics. This site is an information guide to power electronics and SMPS. Here you will find tutorials, tools, reviews, schematics, and other free online resources on all aspects of switching power supply design and selection, information on other energy conversion sources, as well as basic electrical engineering and electronics reference.